2 * Copyright (C) 1991, 1992 Linus Torvalds
6 * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
7 * or rs-channels. It also implements echoing, cooked mode etc.
9 * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0.
11 * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the
12 * tty_struct and tty_queue structures. Previously there was an array
13 * of 256 tty_struct's which was statically allocated, and the
14 * tty_queue structures were allocated at boot time. Both are now
15 * dynamically allocated only when the tty is open.
17 * Also restructured routines so that there is more of a separation
18 * between the high-level tty routines (tty_io.c and tty_ioctl.c) and
19 * the low-level tty routines (serial.c, pty.c, console.c). This
20 * makes for cleaner and more compact code. -TYT, 9/17/92
22 * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines
23 * which can be dynamically activated and de-activated by the line
24 * discipline handling modules (like SLIP).
26 * NOTE: pay no attention to the line discipline code (yet); its
27 * interface is still subject to change in this version...
30 * Added functionality to the OPOST tty handling. No delays, but all
31 * other bits should be there.
32 * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993.
34 * Rewrote canonical mode and added more termios flags.
35 * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94
37 * Reorganized FASYNC support so mouse code can share it.
38 * -- ctm@ardi.com, 9Sep95
40 * New TIOCLINUX variants added.
41 * -- mj@k332.feld.cvut.cz, 19-Nov-95
43 * Restrict vt switching via ioctl()
44 * -- grif@cs.ucr.edu, 5-Dec-95
46 * Move console and virtual terminal code to more appropriate files,
47 * implement CONFIG_VT and generalize console device interface.
48 * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97
50 * Rewrote tty_init_dev and tty_release_dev to eliminate races.
51 * -- Bill Hawes <whawes@star.net>, June 97
53 * Added devfs support.
54 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998
56 * Added support for a Unix98-style ptmx device.
57 * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998
59 * Reduced memory usage for older ARM systems
60 * -- Russell King <rmk@arm.linux.org.uk>
62 * Move do_SAK() into process context. Less stack use in devfs functions.
63 * alloc_tty_struct() always uses kmalloc()
64 * -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01
67 #include <linux/types.h>
68 #include <linux/major.h>
69 #include <linux/errno.h>
70 #include <linux/signal.h>
71 #include <linux/fcntl.h>
72 #include <linux/sched.h>
73 #include <linux/interrupt.h>
74 #include <linux/tty.h>
75 #include <linux/tty_driver.h>
76 #include <linux/tty_flip.h>
77 #include <linux/devpts_fs.h>
78 #include <linux/file.h>
79 #include <linux/fdtable.h>
80 #include <linux/console.h>
81 #include <linux/timer.h>
82 #include <linux/ctype.h>
85 #include <linux/string.h>
86 #include <linux/slab.h>
87 #include <linux/poll.h>
88 #include <linux/proc_fs.h>
89 #include <linux/init.h>
90 #include <linux/module.h>
91 #include <linux/device.h>
92 #include <linux/wait.h>
93 #include <linux/bitops.h>
94 #include <linux/delay.h>
95 #include <linux/seq_file.h>
96 #include <linux/serial.h>
97 #include <linux/ratelimit.h>
99 #include <linux/uaccess.h>
101 #include <linux/kbd_kern.h>
102 #include <linux/vt_kern.h>
103 #include <linux/selection.h>
105 #include <linux/kmod.h>
106 #include <linux/nsproxy.h>
108 #undef TTY_DEBUG_HANGUP
110 #define TTY_PARANOIA_CHECK 1
111 #define CHECK_TTY_COUNT 1
113 struct ktermios tty_std_termios
= { /* for the benefit of tty drivers */
114 .c_iflag
= ICRNL
| IXON
,
115 .c_oflag
= OPOST
| ONLCR
,
116 .c_cflag
= B38400
| CS8
| CREAD
| HUPCL
,
117 .c_lflag
= ISIG
| ICANON
| ECHO
| ECHOE
| ECHOK
|
118 ECHOCTL
| ECHOKE
| IEXTEN
,
124 EXPORT_SYMBOL(tty_std_termios
);
126 /* This list gets poked at by procfs and various bits of boot up code. This
127 could do with some rationalisation such as pulling the tty proc function
130 LIST_HEAD(tty_drivers
); /* linked list of tty drivers */
132 /* Mutex to protect creating and releasing a tty. This is shared with
133 vt.c for deeply disgusting hack reasons */
134 DEFINE_MUTEX(tty_mutex
);
135 EXPORT_SYMBOL(tty_mutex
);
137 /* Spinlock to protect the tty->tty_files list */
138 DEFINE_SPINLOCK(tty_files_lock
);
140 static ssize_t
tty_read(struct file
*, char __user
*, size_t, loff_t
*);
141 static ssize_t
tty_write(struct file
*, const char __user
*, size_t, loff_t
*);
142 ssize_t
redirected_tty_write(struct file
*, const char __user
*,
144 static unsigned int tty_poll(struct file
*, poll_table
*);
145 static int tty_open(struct inode
*, struct file
*);
146 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
);
148 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
151 #define tty_compat_ioctl NULL
153 static int __tty_fasync(int fd
, struct file
*filp
, int on
);
154 static int tty_fasync(int fd
, struct file
*filp
, int on
);
155 static void release_tty(struct tty_struct
*tty
, int idx
);
156 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
);
157 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
);
160 * alloc_tty_struct - allocate a tty object
162 * Return a new empty tty structure. The data fields have not
163 * been initialized in any way but has been zeroed
168 struct tty_struct
*alloc_tty_struct(void)
170 return kzalloc(sizeof(struct tty_struct
), GFP_KERNEL
);
174 * free_tty_struct - free a disused tty
175 * @tty: tty struct to free
177 * Free the write buffers, tty queue and tty memory itself.
179 * Locking: none. Must be called after tty is definitely unused
182 void free_tty_struct(struct tty_struct
*tty
)
185 put_device(tty
->dev
);
186 kfree(tty
->write_buf
);
187 tty_buffer_free_all(tty
);
188 tty
->magic
= 0xDEADDEAD;
192 static inline struct tty_struct
*file_tty(struct file
*file
)
194 return ((struct tty_file_private
*)file
->private_data
)->tty
;
197 int tty_alloc_file(struct file
*file
)
199 struct tty_file_private
*priv
;
201 priv
= kmalloc(sizeof(*priv
), GFP_KERNEL
);
205 file
->private_data
= priv
;
210 /* Associate a new file with the tty structure */
211 void tty_add_file(struct tty_struct
*tty
, struct file
*file
)
213 struct tty_file_private
*priv
= file
->private_data
;
218 spin_lock(&tty_files_lock
);
219 list_add(&priv
->list
, &tty
->tty_files
);
220 spin_unlock(&tty_files_lock
);
224 * tty_free_file - free file->private_data
226 * This shall be used only for fail path handling when tty_add_file was not
229 void tty_free_file(struct file
*file
)
231 struct tty_file_private
*priv
= file
->private_data
;
233 file
->private_data
= NULL
;
237 /* Delete file from its tty */
238 void tty_del_file(struct file
*file
)
240 struct tty_file_private
*priv
= file
->private_data
;
242 spin_lock(&tty_files_lock
);
243 list_del(&priv
->list
);
244 spin_unlock(&tty_files_lock
);
249 #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base)
252 * tty_name - return tty naming
253 * @tty: tty structure
254 * @buf: buffer for output
256 * Convert a tty structure into a name. The name reflects the kernel
257 * naming policy and if udev is in use may not reflect user space
262 char *tty_name(struct tty_struct
*tty
, char *buf
)
264 if (!tty
) /* Hmm. NULL pointer. That's fun. */
265 strcpy(buf
, "NULL tty");
267 strcpy(buf
, tty
->name
);
271 EXPORT_SYMBOL(tty_name
);
273 int tty_paranoia_check(struct tty_struct
*tty
, struct inode
*inode
,
276 #ifdef TTY_PARANOIA_CHECK
279 "null TTY for (%d:%d) in %s\n",
280 imajor(inode
), iminor(inode
), routine
);
283 if (tty
->magic
!= TTY_MAGIC
) {
285 "bad magic number for tty struct (%d:%d) in %s\n",
286 imajor(inode
), iminor(inode
), routine
);
293 static int check_tty_count(struct tty_struct
*tty
, const char *routine
)
295 #ifdef CHECK_TTY_COUNT
299 spin_lock(&tty_files_lock
);
300 list_for_each(p
, &tty
->tty_files
) {
303 spin_unlock(&tty_files_lock
);
304 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
305 tty
->driver
->subtype
== PTY_TYPE_SLAVE
&&
306 tty
->link
&& tty
->link
->count
)
308 if (tty
->count
!= count
) {
309 printk(KERN_WARNING
"Warning: dev (%s) tty->count(%d) "
310 "!= #fd's(%d) in %s\n",
311 tty
->name
, tty
->count
, count
, routine
);
319 * get_tty_driver - find device of a tty
320 * @dev_t: device identifier
321 * @index: returns the index of the tty
323 * This routine returns a tty driver structure, given a device number
324 * and also passes back the index number.
326 * Locking: caller must hold tty_mutex
329 static struct tty_driver
*get_tty_driver(dev_t device
, int *index
)
331 struct tty_driver
*p
;
333 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
334 dev_t base
= MKDEV(p
->major
, p
->minor_start
);
335 if (device
< base
|| device
>= base
+ p
->num
)
337 *index
= device
- base
;
338 return tty_driver_kref_get(p
);
343 #ifdef CONFIG_CONSOLE_POLL
346 * tty_find_polling_driver - find device of a polled tty
347 * @name: name string to match
348 * @line: pointer to resulting tty line nr
350 * This routine returns a tty driver structure, given a name
351 * and the condition that the tty driver is capable of polled
354 struct tty_driver
*tty_find_polling_driver(char *name
, int *line
)
356 struct tty_driver
*p
, *res
= NULL
;
361 for (str
= name
; *str
; str
++)
362 if ((*str
>= '0' && *str
<= '9') || *str
== ',')
368 tty_line
= simple_strtoul(str
, &str
, 10);
370 mutex_lock(&tty_mutex
);
371 /* Search through the tty devices to look for a match */
372 list_for_each_entry(p
, &tty_drivers
, tty_drivers
) {
373 if (strncmp(name
, p
->name
, len
) != 0)
381 if (tty_line
>= 0 && tty_line
< p
->num
&& p
->ops
&&
382 p
->ops
->poll_init
&& !p
->ops
->poll_init(p
, tty_line
, stp
)) {
383 res
= tty_driver_kref_get(p
);
388 mutex_unlock(&tty_mutex
);
392 EXPORT_SYMBOL_GPL(tty_find_polling_driver
);
396 * tty_check_change - check for POSIX terminal changes
399 * If we try to write to, or set the state of, a terminal and we're
400 * not in the foreground, send a SIGTTOU. If the signal is blocked or
401 * ignored, go ahead and perform the operation. (POSIX 7.2)
406 int tty_check_change(struct tty_struct
*tty
)
411 if (current
->signal
->tty
!= tty
)
414 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
417 printk(KERN_WARNING
"tty_check_change: tty->pgrp == NULL!\n");
420 if (task_pgrp(current
) == tty
->pgrp
)
422 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
423 if (is_ignored(SIGTTOU
))
425 if (is_current_pgrp_orphaned()) {
429 kill_pgrp(task_pgrp(current
), SIGTTOU
, 1);
430 set_thread_flag(TIF_SIGPENDING
);
435 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
439 EXPORT_SYMBOL(tty_check_change
);
441 static ssize_t
hung_up_tty_read(struct file
*file
, char __user
*buf
,
442 size_t count
, loff_t
*ppos
)
447 static ssize_t
hung_up_tty_write(struct file
*file
, const char __user
*buf
,
448 size_t count
, loff_t
*ppos
)
453 /* No kernel lock held - none needed ;) */
454 static unsigned int hung_up_tty_poll(struct file
*filp
, poll_table
*wait
)
456 return POLLIN
| POLLOUT
| POLLERR
| POLLHUP
| POLLRDNORM
| POLLWRNORM
;
459 static long hung_up_tty_ioctl(struct file
*file
, unsigned int cmd
,
462 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
465 static long hung_up_tty_compat_ioctl(struct file
*file
,
466 unsigned int cmd
, unsigned long arg
)
468 return cmd
== TIOCSPGRP
? -ENOTTY
: -EIO
;
471 static const struct file_operations tty_fops
= {
476 .unlocked_ioctl
= tty_ioctl
,
477 .compat_ioctl
= tty_compat_ioctl
,
479 .release
= tty_release
,
480 .fasync
= tty_fasync
,
483 static const struct file_operations console_fops
= {
486 .write
= redirected_tty_write
,
488 .unlocked_ioctl
= tty_ioctl
,
489 .compat_ioctl
= tty_compat_ioctl
,
491 .release
= tty_release
,
492 .fasync
= tty_fasync
,
495 static const struct file_operations hung_up_tty_fops
= {
497 .read
= hung_up_tty_read
,
498 .write
= hung_up_tty_write
,
499 .poll
= hung_up_tty_poll
,
500 .unlocked_ioctl
= hung_up_tty_ioctl
,
501 .compat_ioctl
= hung_up_tty_compat_ioctl
,
502 .release
= tty_release
,
505 static DEFINE_SPINLOCK(redirect_lock
);
506 static struct file
*redirect
;
509 * tty_wakeup - request more data
512 * Internal and external helper for wakeups of tty. This function
513 * informs the line discipline if present that the driver is ready
514 * to receive more output data.
517 void tty_wakeup(struct tty_struct
*tty
)
519 struct tty_ldisc
*ld
;
521 if (test_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
)) {
522 ld
= tty_ldisc_ref(tty
);
524 if (ld
->ops
->write_wakeup
)
525 ld
->ops
->write_wakeup(tty
);
529 wake_up_interruptible_poll(&tty
->write_wait
, POLLOUT
);
532 EXPORT_SYMBOL_GPL(tty_wakeup
);
535 * __tty_hangup - actual handler for hangup events
538 * This can be called by the "eventd" kernel thread. That is process
539 * synchronous but doesn't hold any locks, so we need to make sure we
540 * have the appropriate locks for what we're doing.
542 * The hangup event clears any pending redirections onto the hung up
543 * device. It ensures future writes will error and it does the needed
544 * line discipline hangup and signal delivery. The tty object itself
549 * redirect lock for undoing redirection
550 * file list lock for manipulating list of ttys
551 * tty_ldisc_lock from called functions
552 * termios_mutex resetting termios data
553 * tasklist_lock to walk task list for hangup event
554 * ->siglock to protect ->signal/->sighand
556 void __tty_hangup(struct tty_struct
*tty
)
558 struct file
*cons_filp
= NULL
;
559 struct file
*filp
, *f
= NULL
;
560 struct task_struct
*p
;
561 struct tty_file_private
*priv
;
562 int closecount
= 0, n
;
570 spin_lock(&redirect_lock
);
571 if (redirect
&& file_tty(redirect
) == tty
) {
575 spin_unlock(&redirect_lock
);
579 /* some functions below drop BTM, so we need this bit */
580 set_bit(TTY_HUPPING
, &tty
->flags
);
582 /* inuse_filps is protected by the single tty lock,
583 this really needs to change if we want to flush the
584 workqueue with the lock held */
585 check_tty_count(tty
, "tty_hangup");
587 spin_lock(&tty_files_lock
);
588 /* This breaks for file handles being sent over AF_UNIX sockets ? */
589 list_for_each_entry(priv
, &tty
->tty_files
, list
) {
591 if (filp
->f_op
->write
== redirected_tty_write
)
593 if (filp
->f_op
->write
!= tty_write
)
596 __tty_fasync(-1, filp
, 0); /* can't block */
597 filp
->f_op
= &hung_up_tty_fops
;
599 spin_unlock(&tty_files_lock
);
602 * it drops BTM and thus races with reopen
603 * we protect the race by TTY_HUPPING
605 tty_ldisc_hangup(tty
);
607 read_lock(&tasklist_lock
);
609 do_each_pid_task(tty
->session
, PIDTYPE_SID
, p
) {
610 spin_lock_irq(&p
->sighand
->siglock
);
611 if (p
->signal
->tty
== tty
) {
612 p
->signal
->tty
= NULL
;
613 /* We defer the dereferences outside fo
617 if (!p
->signal
->leader
) {
618 spin_unlock_irq(&p
->sighand
->siglock
);
621 __group_send_sig_info(SIGHUP
, SEND_SIG_PRIV
, p
);
622 __group_send_sig_info(SIGCONT
, SEND_SIG_PRIV
, p
);
623 put_pid(p
->signal
->tty_old_pgrp
); /* A noop */
624 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
626 p
->signal
->tty_old_pgrp
= get_pid(tty
->pgrp
);
627 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
628 spin_unlock_irq(&p
->sighand
->siglock
);
629 } while_each_pid_task(tty
->session
, PIDTYPE_SID
, p
);
631 read_unlock(&tasklist_lock
);
633 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
634 clear_bit(TTY_THROTTLED
, &tty
->flags
);
635 clear_bit(TTY_PUSH
, &tty
->flags
);
636 clear_bit(TTY_DO_WRITE_WAKEUP
, &tty
->flags
);
637 put_pid(tty
->session
);
641 tty
->ctrl_status
= 0;
642 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
644 /* Account for the p->signal references we killed */
649 * If one of the devices matches a console pointer, we
650 * cannot just call hangup() because that will cause
651 * tty->count and state->count to go out of sync.
652 * So we just call close() the right number of times.
656 for (n
= 0; n
< closecount
; n
++)
657 tty
->ops
->close(tty
, cons_filp
);
658 } else if (tty
->ops
->hangup
)
659 (tty
->ops
->hangup
)(tty
);
661 * We don't want to have driver/ldisc interactions beyond
662 * the ones we did here. The driver layer expects no
663 * calls after ->hangup() from the ldisc side. However we
664 * can't yet guarantee all that.
666 set_bit(TTY_HUPPED
, &tty
->flags
);
667 clear_bit(TTY_HUPPING
, &tty
->flags
);
668 tty_ldisc_enable(tty
);
676 static void do_tty_hangup(struct work_struct
*work
)
678 struct tty_struct
*tty
=
679 container_of(work
, struct tty_struct
, hangup_work
);
685 * tty_hangup - trigger a hangup event
686 * @tty: tty to hangup
688 * A carrier loss (virtual or otherwise) has occurred on this like
689 * schedule a hangup sequence to run after this event.
692 void tty_hangup(struct tty_struct
*tty
)
694 #ifdef TTY_DEBUG_HANGUP
696 printk(KERN_DEBUG
"%s hangup...\n", tty_name(tty
, buf
));
698 schedule_work(&tty
->hangup_work
);
701 EXPORT_SYMBOL(tty_hangup
);
704 * tty_vhangup - process vhangup
705 * @tty: tty to hangup
707 * The user has asked via system call for the terminal to be hung up.
708 * We do this synchronously so that when the syscall returns the process
709 * is complete. That guarantee is necessary for security reasons.
712 void tty_vhangup(struct tty_struct
*tty
)
714 #ifdef TTY_DEBUG_HANGUP
717 printk(KERN_DEBUG
"%s vhangup...\n", tty_name(tty
, buf
));
722 EXPORT_SYMBOL(tty_vhangup
);
726 * tty_vhangup_self - process vhangup for own ctty
728 * Perform a vhangup on the current controlling tty
731 void tty_vhangup_self(void)
733 struct tty_struct
*tty
;
735 tty
= get_current_tty();
743 * tty_hung_up_p - was tty hung up
744 * @filp: file pointer of tty
746 * Return true if the tty has been subject to a vhangup or a carrier
750 int tty_hung_up_p(struct file
*filp
)
752 return (filp
->f_op
== &hung_up_tty_fops
);
755 EXPORT_SYMBOL(tty_hung_up_p
);
757 static void session_clear_tty(struct pid
*session
)
759 struct task_struct
*p
;
760 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
762 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
766 * disassociate_ctty - disconnect controlling tty
767 * @on_exit: true if exiting so need to "hang up" the session
769 * This function is typically called only by the session leader, when
770 * it wants to disassociate itself from its controlling tty.
772 * It performs the following functions:
773 * (1) Sends a SIGHUP and SIGCONT to the foreground process group
774 * (2) Clears the tty from being controlling the session
775 * (3) Clears the controlling tty for all processes in the
778 * The argument on_exit is set to 1 if called when a process is
779 * exiting; it is 0 if called by the ioctl TIOCNOTTY.
782 * BTM is taken for hysterical raisins, and held when
783 * called from no_tty().
784 * tty_mutex is taken to protect tty
785 * ->siglock is taken to protect ->signal/->sighand
786 * tasklist_lock is taken to walk process list for sessions
787 * ->siglock is taken to protect ->signal/->sighand
790 void disassociate_ctty(int on_exit
)
792 struct tty_struct
*tty
;
794 if (!current
->signal
->leader
)
797 tty
= get_current_tty();
799 struct pid
*tty_pgrp
= get_pid(tty
->pgrp
);
801 if (tty
->driver
->type
!= TTY_DRIVER_TYPE_PTY
)
806 kill_pgrp(tty_pgrp
, SIGHUP
, on_exit
);
808 kill_pgrp(tty_pgrp
, SIGCONT
, on_exit
);
811 } else if (on_exit
) {
812 struct pid
*old_pgrp
;
813 spin_lock_irq(¤t
->sighand
->siglock
);
814 old_pgrp
= current
->signal
->tty_old_pgrp
;
815 current
->signal
->tty_old_pgrp
= NULL
;
816 spin_unlock_irq(¤t
->sighand
->siglock
);
818 kill_pgrp(old_pgrp
, SIGHUP
, on_exit
);
819 kill_pgrp(old_pgrp
, SIGCONT
, on_exit
);
825 spin_lock_irq(¤t
->sighand
->siglock
);
826 put_pid(current
->signal
->tty_old_pgrp
);
827 current
->signal
->tty_old_pgrp
= NULL
;
828 spin_unlock_irq(¤t
->sighand
->siglock
);
830 tty
= get_current_tty();
833 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
834 put_pid(tty
->session
);
838 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
841 #ifdef TTY_DEBUG_HANGUP
842 printk(KERN_DEBUG
"error attempted to write to tty [0x%p]"
847 /* Now clear signal->tty under the lock */
848 read_lock(&tasklist_lock
);
849 session_clear_tty(task_session(current
));
850 read_unlock(&tasklist_lock
);
855 * no_tty - Ensure the current process does not have a controlling tty
859 /* FIXME: Review locking here. The tty_lock never covered any race
860 between a new association and proc_clear_tty but possible we need
861 to protect against this anyway */
862 struct task_struct
*tsk
= current
;
863 disassociate_ctty(0);
869 * stop_tty - propagate flow control
872 * Perform flow control to the driver. For PTY/TTY pairs we
873 * must also propagate the TIOCKPKT status. May be called
874 * on an already stopped device and will not re-call the driver
877 * This functionality is used by both the line disciplines for
878 * halting incoming flow and by the driver. It may therefore be
879 * called from any context, may be under the tty atomic_write_lock
883 * Uses the tty control lock internally
886 void stop_tty(struct tty_struct
*tty
)
889 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
891 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
895 if (tty
->link
&& tty
->link
->packet
) {
896 tty
->ctrl_status
&= ~TIOCPKT_START
;
897 tty
->ctrl_status
|= TIOCPKT_STOP
;
898 wake_up_interruptible_poll(&tty
->link
->read_wait
, POLLIN
);
900 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
902 (tty
->ops
->stop
)(tty
);
905 EXPORT_SYMBOL(stop_tty
);
908 * start_tty - propagate flow control
911 * Start a tty that has been stopped if at all possible. Perform
912 * any necessary wakeups and propagate the TIOCPKT status. If this
913 * is the tty was previous stopped and is being started then the
914 * driver start method is invoked and the line discipline woken.
920 void start_tty(struct tty_struct
*tty
)
923 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
924 if (!tty
->stopped
|| tty
->flow_stopped
) {
925 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
929 if (tty
->link
&& tty
->link
->packet
) {
930 tty
->ctrl_status
&= ~TIOCPKT_STOP
;
931 tty
->ctrl_status
|= TIOCPKT_START
;
932 wake_up_interruptible_poll(&tty
->link
->read_wait
, POLLIN
);
934 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
936 (tty
->ops
->start
)(tty
);
937 /* If we have a running line discipline it may need kicking */
941 EXPORT_SYMBOL(start_tty
);
944 * tty_read - read method for tty device files
945 * @file: pointer to tty file
947 * @count: size of user buffer
950 * Perform the read system call function on this terminal device. Checks
951 * for hung up devices before calling the line discipline method.
954 * Locks the line discipline internally while needed. Multiple
955 * read calls may be outstanding in parallel.
958 static ssize_t
tty_read(struct file
*file
, char __user
*buf
, size_t count
,
962 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
963 struct tty_struct
*tty
= file_tty(file
);
964 struct tty_ldisc
*ld
;
966 if (tty_paranoia_check(tty
, inode
, "tty_read"))
968 if (!tty
|| (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
971 /* We want to wait for the line discipline to sort out in this
973 ld
= tty_ldisc_ref_wait(tty
);
975 i
= (ld
->ops
->read
)(tty
, file
, buf
, count
);
980 inode
->i_atime
= current_fs_time(inode
->i_sb
);
984 void tty_write_unlock(struct tty_struct
*tty
)
985 __releases(&tty
->atomic_write_lock
)
987 mutex_unlock(&tty
->atomic_write_lock
);
988 wake_up_interruptible_poll(&tty
->write_wait
, POLLOUT
);
991 int tty_write_lock(struct tty_struct
*tty
, int ndelay
)
992 __acquires(&tty
->atomic_write_lock
)
994 if (!mutex_trylock(&tty
->atomic_write_lock
)) {
997 if (mutex_lock_interruptible(&tty
->atomic_write_lock
))
1004 * Split writes up in sane blocksizes to avoid
1005 * denial-of-service type attacks
1007 static inline ssize_t
do_tty_write(
1008 ssize_t (*write
)(struct tty_struct
*, struct file
*, const unsigned char *, size_t),
1009 struct tty_struct
*tty
,
1011 const char __user
*buf
,
1014 ssize_t ret
, written
= 0;
1017 ret
= tty_write_lock(tty
, file
->f_flags
& O_NDELAY
);
1022 * We chunk up writes into a temporary buffer. This
1023 * simplifies low-level drivers immensely, since they
1024 * don't have locking issues and user mode accesses.
1026 * But if TTY_NO_WRITE_SPLIT is set, we should use a
1029 * The default chunk-size is 2kB, because the NTTY
1030 * layer has problems with bigger chunks. It will
1031 * claim to be able to handle more characters than
1034 * FIXME: This can probably go away now except that 64K chunks
1035 * are too likely to fail unless switched to vmalloc...
1038 if (test_bit(TTY_NO_WRITE_SPLIT
, &tty
->flags
))
1043 /* write_buf/write_cnt is protected by the atomic_write_lock mutex */
1044 if (tty
->write_cnt
< chunk
) {
1045 unsigned char *buf_chunk
;
1050 buf_chunk
= kmalloc(chunk
, GFP_KERNEL
);
1055 kfree(tty
->write_buf
);
1056 tty
->write_cnt
= chunk
;
1057 tty
->write_buf
= buf_chunk
;
1060 /* Do the write .. */
1062 size_t size
= count
;
1066 if (copy_from_user(tty
->write_buf
, buf
, size
))
1068 ret
= write(tty
, file
, tty
->write_buf
, size
);
1077 if (signal_pending(current
))
1082 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1083 inode
->i_mtime
= current_fs_time(inode
->i_sb
);
1087 tty_write_unlock(tty
);
1092 * tty_write_message - write a message to a certain tty, not just the console.
1093 * @tty: the destination tty_struct
1094 * @msg: the message to write
1096 * This is used for messages that need to be redirected to a specific tty.
1097 * We don't put it into the syslog queue right now maybe in the future if
1100 * We must still hold the BTM and test the CLOSING flag for the moment.
1103 void tty_write_message(struct tty_struct
*tty
, char *msg
)
1106 mutex_lock(&tty
->atomic_write_lock
);
1108 if (tty
->ops
->write
&& !test_bit(TTY_CLOSING
, &tty
->flags
)) {
1110 tty
->ops
->write(tty
, msg
, strlen(msg
));
1113 tty_write_unlock(tty
);
1120 * tty_write - write method for tty device file
1121 * @file: tty file pointer
1122 * @buf: user data to write
1123 * @count: bytes to write
1126 * Write data to a tty device via the line discipline.
1129 * Locks the line discipline as required
1130 * Writes to the tty driver are serialized by the atomic_write_lock
1131 * and are then processed in chunks to the device. The line discipline
1132 * write method will not be invoked in parallel for each device.
1135 static ssize_t
tty_write(struct file
*file
, const char __user
*buf
,
1136 size_t count
, loff_t
*ppos
)
1138 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1139 struct tty_struct
*tty
= file_tty(file
);
1140 struct tty_ldisc
*ld
;
1143 if (tty_paranoia_check(tty
, inode
, "tty_write"))
1145 if (!tty
|| !tty
->ops
->write
||
1146 (test_bit(TTY_IO_ERROR
, &tty
->flags
)))
1148 /* Short term debug to catch buggy drivers */
1149 if (tty
->ops
->write_room
== NULL
)
1150 printk(KERN_ERR
"tty driver %s lacks a write_room method.\n",
1152 ld
= tty_ldisc_ref_wait(tty
);
1153 if (!ld
->ops
->write
)
1156 ret
= do_tty_write(ld
->ops
->write
, tty
, file
, buf
, count
);
1157 tty_ldisc_deref(ld
);
1161 ssize_t
redirected_tty_write(struct file
*file
, const char __user
*buf
,
1162 size_t count
, loff_t
*ppos
)
1164 struct file
*p
= NULL
;
1166 spin_lock(&redirect_lock
);
1171 spin_unlock(&redirect_lock
);
1175 res
= vfs_write(p
, buf
, count
, &p
->f_pos
);
1179 return tty_write(file
, buf
, count
, ppos
);
1182 static char ptychar
[] = "pqrstuvwxyzabcde";
1185 * pty_line_name - generate name for a pty
1186 * @driver: the tty driver in use
1187 * @index: the minor number
1188 * @p: output buffer of at least 6 bytes
1190 * Generate a name from a driver reference and write it to the output
1195 static void pty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1197 int i
= index
+ driver
->name_base
;
1198 /* ->name is initialized to "ttyp", but "tty" is expected */
1199 sprintf(p
, "%s%c%x",
1200 driver
->subtype
== PTY_TYPE_SLAVE
? "tty" : driver
->name
,
1201 ptychar
[i
>> 4 & 0xf], i
& 0xf);
1205 * tty_line_name - generate name for a tty
1206 * @driver: the tty driver in use
1207 * @index: the minor number
1208 * @p: output buffer of at least 7 bytes
1210 * Generate a name from a driver reference and write it to the output
1215 static void tty_line_name(struct tty_driver
*driver
, int index
, char *p
)
1217 sprintf(p
, "%s%d", driver
->name
, index
+ driver
->name_base
);
1221 * tty_driver_lookup_tty() - find an existing tty, if any
1222 * @driver: the driver for the tty
1223 * @idx: the minor number
1225 * Return the tty, if found or ERR_PTR() otherwise.
1227 * Locking: tty_mutex must be held. If tty is found, the mutex must
1228 * be held until the 'fast-open' is also done. Will change once we
1229 * have refcounting in the driver and per driver locking
1231 static struct tty_struct
*tty_driver_lookup_tty(struct tty_driver
*driver
,
1232 struct inode
*inode
, int idx
)
1234 if (driver
->ops
->lookup
)
1235 return driver
->ops
->lookup(driver
, inode
, idx
);
1237 return driver
->ttys
[idx
];
1241 * tty_init_termios - helper for termios setup
1242 * @tty: the tty to set up
1244 * Initialise the termios structures for this tty. Thus runs under
1245 * the tty_mutex currently so we can be relaxed about ordering.
1248 int tty_init_termios(struct tty_struct
*tty
)
1250 struct ktermios
*tp
;
1251 int idx
= tty
->index
;
1253 tp
= tty
->driver
->termios
[idx
];
1255 tp
= kzalloc(sizeof(struct ktermios
[2]), GFP_KERNEL
);
1258 memcpy(tp
, &tty
->driver
->init_termios
,
1259 sizeof(struct ktermios
));
1260 tty
->driver
->termios
[idx
] = tp
;
1263 tty
->termios_locked
= tp
+ 1;
1265 /* Compatibility until drivers always set this */
1266 tty
->termios
->c_ispeed
= tty_termios_input_baud_rate(tty
->termios
);
1267 tty
->termios
->c_ospeed
= tty_termios_baud_rate(tty
->termios
);
1270 EXPORT_SYMBOL_GPL(tty_init_termios
);
1272 int tty_standard_install(struct tty_driver
*driver
, struct tty_struct
*tty
)
1274 int ret
= tty_init_termios(tty
);
1278 tty_driver_kref_get(driver
);
1280 driver
->ttys
[tty
->index
] = tty
;
1283 EXPORT_SYMBOL_GPL(tty_standard_install
);
1286 * tty_driver_install_tty() - install a tty entry in the driver
1287 * @driver: the driver for the tty
1290 * Install a tty object into the driver tables. The tty->index field
1291 * will be set by the time this is called. This method is responsible
1292 * for ensuring any need additional structures are allocated and
1295 * Locking: tty_mutex for now
1297 static int tty_driver_install_tty(struct tty_driver
*driver
,
1298 struct tty_struct
*tty
)
1300 return driver
->ops
->install
? driver
->ops
->install(driver
, tty
) :
1301 tty_standard_install(driver
, tty
);
1305 * tty_driver_remove_tty() - remove a tty from the driver tables
1306 * @driver: the driver for the tty
1307 * @idx: the minor number
1309 * Remvoe a tty object from the driver tables. The tty->index field
1310 * will be set by the time this is called.
1312 * Locking: tty_mutex for now
1314 void tty_driver_remove_tty(struct tty_driver
*driver
, struct tty_struct
*tty
)
1316 if (driver
->ops
->remove
)
1317 driver
->ops
->remove(driver
, tty
);
1319 driver
->ttys
[tty
->index
] = NULL
;
1323 * tty_reopen() - fast re-open of an open tty
1324 * @tty - the tty to open
1326 * Return 0 on success, -errno on error.
1328 * Locking: tty_mutex must be held from the time the tty was found
1329 * till this open completes.
1331 static int tty_reopen(struct tty_struct
*tty
)
1333 struct tty_driver
*driver
= tty
->driver
;
1335 if (test_bit(TTY_CLOSING
, &tty
->flags
) ||
1336 test_bit(TTY_HUPPING
, &tty
->flags
) ||
1337 test_bit(TTY_LDISC_CHANGING
, &tty
->flags
))
1340 if (driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1341 driver
->subtype
== PTY_TYPE_MASTER
) {
1343 * special case for PTY masters: only one open permitted,
1344 * and the slave side open count is incremented as well.
1353 mutex_lock(&tty
->ldisc_mutex
);
1354 WARN_ON(!test_bit(TTY_LDISC
, &tty
->flags
));
1355 mutex_unlock(&tty
->ldisc_mutex
);
1361 * tty_init_dev - initialise a tty device
1362 * @driver: tty driver we are opening a device on
1363 * @idx: device index
1364 * @ret_tty: returned tty structure
1366 * Prepare a tty device. This may not be a "new" clean device but
1367 * could also be an active device. The pty drivers require special
1368 * handling because of this.
1371 * The function is called under the tty_mutex, which
1372 * protects us from the tty struct or driver itself going away.
1374 * On exit the tty device has the line discipline attached and
1375 * a reference count of 1. If a pair was created for pty/tty use
1376 * and the other was a pty master then it too has a reference count of 1.
1378 * WSH 06/09/97: Rewritten to remove races and properly clean up after a
1379 * failed open. The new code protects the open with a mutex, so it's
1380 * really quite straightforward. The mutex locking can probably be
1381 * relaxed for the (most common) case of reopening a tty.
1384 struct tty_struct
*tty_init_dev(struct tty_driver
*driver
, int idx
)
1386 struct tty_struct
*tty
;
1390 * First time open is complex, especially for PTY devices.
1391 * This code guarantees that either everything succeeds and the
1392 * TTY is ready for operation, or else the table slots are vacated
1393 * and the allocated memory released. (Except that the termios
1394 * and locked termios may be retained.)
1397 if (!try_module_get(driver
->owner
))
1398 return ERR_PTR(-ENODEV
);
1400 tty
= alloc_tty_struct();
1403 goto err_module_put
;
1405 initialize_tty_struct(tty
, driver
, idx
);
1408 retval
= tty_driver_install_tty(driver
, tty
);
1410 goto err_deinit_tty
;
1413 * Structures all installed ... call the ldisc open routines.
1414 * If we fail here just call release_tty to clean up. No need
1415 * to decrement the use counts, as release_tty doesn't care.
1417 retval
= tty_ldisc_setup(tty
, tty
->link
);
1419 goto err_release_tty
;
1420 /* Return the tty locked so that it cannot vanish under the caller */
1425 deinitialize_tty_struct(tty
);
1426 free_tty_struct(tty
);
1428 module_put(driver
->owner
);
1429 return ERR_PTR(retval
);
1431 /* call the tty release_tty routine to clean out this slot */
1434 printk_ratelimited(KERN_INFO
"tty_init_dev: ldisc open failed, "
1435 "clearing slot %d\n", idx
);
1436 release_tty(tty
, idx
);
1437 return ERR_PTR(retval
);
1440 void tty_free_termios(struct tty_struct
*tty
)
1442 struct ktermios
*tp
;
1443 int idx
= tty
->index
;
1444 /* Kill this flag and push into drivers for locking etc */
1445 if (tty
->driver
->flags
& TTY_DRIVER_RESET_TERMIOS
) {
1446 /* FIXME: Locking on ->termios array */
1448 tty
->driver
->termios
[idx
] = NULL
;
1452 EXPORT_SYMBOL(tty_free_termios
);
1454 void tty_shutdown(struct tty_struct
*tty
)
1456 tty_driver_remove_tty(tty
->driver
, tty
);
1457 tty_free_termios(tty
);
1459 EXPORT_SYMBOL(tty_shutdown
);
1462 * release_one_tty - release tty structure memory
1463 * @kref: kref of tty we are obliterating
1465 * Releases memory associated with a tty structure, and clears out the
1466 * driver table slots. This function is called when a device is no longer
1467 * in use. It also gets called when setup of a device fails.
1470 * tty_mutex - sometimes only
1471 * takes the file list lock internally when working on the list
1472 * of ttys that the driver keeps.
1474 * This method gets called from a work queue so that the driver private
1475 * cleanup ops can sleep (needed for USB at least)
1477 static void release_one_tty(struct work_struct
*work
)
1479 struct tty_struct
*tty
=
1480 container_of(work
, struct tty_struct
, hangup_work
);
1481 struct tty_driver
*driver
= tty
->driver
;
1483 if (tty
->ops
->cleanup
)
1484 tty
->ops
->cleanup(tty
);
1487 tty_driver_kref_put(driver
);
1488 module_put(driver
->owner
);
1490 spin_lock(&tty_files_lock
);
1491 list_del_init(&tty
->tty_files
);
1492 spin_unlock(&tty_files_lock
);
1495 put_pid(tty
->session
);
1496 free_tty_struct(tty
);
1499 static void queue_release_one_tty(struct kref
*kref
)
1501 struct tty_struct
*tty
= container_of(kref
, struct tty_struct
, kref
);
1503 if (tty
->ops
->shutdown
)
1504 tty
->ops
->shutdown(tty
);
1508 /* The hangup queue is now free so we can reuse it rather than
1509 waste a chunk of memory for each port */
1510 INIT_WORK(&tty
->hangup_work
, release_one_tty
);
1511 schedule_work(&tty
->hangup_work
);
1515 * tty_kref_put - release a tty kref
1518 * Release a reference to a tty device and if need be let the kref
1519 * layer destruct the object for us
1522 void tty_kref_put(struct tty_struct
*tty
)
1525 kref_put(&tty
->kref
, queue_release_one_tty
);
1527 EXPORT_SYMBOL(tty_kref_put
);
1530 * release_tty - release tty structure memory
1532 * Release both @tty and a possible linked partner (think pty pair),
1533 * and decrement the refcount of the backing module.
1536 * tty_mutex - sometimes only
1537 * takes the file list lock internally when working on the list
1538 * of ttys that the driver keeps.
1539 * FIXME: should we require tty_mutex is held here ??
1542 static void release_tty(struct tty_struct
*tty
, int idx
)
1544 /* This should always be true but check for the moment */
1545 WARN_ON(tty
->index
!= idx
);
1548 tty_kref_put(tty
->link
);
1553 * tty_release_checks - check a tty before real release
1554 * @tty: tty to check
1555 * @o_tty: link of @tty (if any)
1556 * @idx: index of the tty
1558 * Performs some paranoid checking before true release of the @tty.
1559 * This is a no-op unless TTY_PARANOIA_CHECK is defined.
1561 static int tty_release_checks(struct tty_struct
*tty
, struct tty_struct
*o_tty
,
1564 #ifdef TTY_PARANOIA_CHECK
1565 if (idx
< 0 || idx
>= tty
->driver
->num
) {
1566 printk(KERN_DEBUG
"%s: bad idx when trying to free (%s)\n",
1567 __func__
, tty
->name
);
1571 /* not much to check for devpts */
1572 if (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
)
1575 if (tty
!= tty
->driver
->ttys
[idx
]) {
1576 printk(KERN_DEBUG
"%s: driver.table[%d] not tty for (%s)\n",
1577 __func__
, idx
, tty
->name
);
1580 if (tty
->termios
!= tty
->driver
->termios
[idx
]) {
1581 printk(KERN_DEBUG
"%s: driver.termios[%d] not termios for (%s)\n",
1582 __func__
, idx
, tty
->name
);
1585 if (tty
->driver
->other
) {
1586 if (o_tty
!= tty
->driver
->other
->ttys
[idx
]) {
1587 printk(KERN_DEBUG
"%s: other->table[%d] not o_tty for (%s)\n",
1588 __func__
, idx
, tty
->name
);
1591 if (o_tty
->termios
!= tty
->driver
->other
->termios
[idx
]) {
1592 printk(KERN_DEBUG
"%s: other->termios[%d] not o_termios for (%s)\n",
1593 __func__
, idx
, tty
->name
);
1596 if (o_tty
->link
!= tty
) {
1597 printk(KERN_DEBUG
"%s: bad pty pointers\n", __func__
);
1606 * tty_release - vfs callback for close
1607 * @inode: inode of tty
1608 * @filp: file pointer for handle to tty
1610 * Called the last time each file handle is closed that references
1611 * this tty. There may however be several such references.
1614 * Takes bkl. See tty_release_dev
1616 * Even releasing the tty structures is a tricky business.. We have
1617 * to be very careful that the structures are all released at the
1618 * same time, as interrupts might otherwise get the wrong pointers.
1620 * WSH 09/09/97: rewritten to avoid some nasty race conditions that could
1621 * lead to double frees or releasing memory still in use.
1624 int tty_release(struct inode
*inode
, struct file
*filp
)
1626 struct tty_struct
*tty
= file_tty(filp
);
1627 struct tty_struct
*o_tty
;
1628 int pty_master
, tty_closing
, o_tty_closing
, do_sleep
;
1633 if (tty_paranoia_check(tty
, inode
, __func__
))
1637 check_tty_count(tty
, __func__
);
1639 __tty_fasync(-1, filp
, 0);
1642 pty_master
= (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1643 tty
->driver
->subtype
== PTY_TYPE_MASTER
);
1644 devpts
= (tty
->driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) != 0;
1645 /* Review: parallel close */
1648 if (tty_release_checks(tty
, o_tty
, idx
)) {
1653 #ifdef TTY_DEBUG_HANGUP
1654 printk(KERN_DEBUG
"%s: %s (tty count=%d)...\n", __func__
,
1655 tty_name(tty
, buf
), tty
->count
);
1658 if (tty
->ops
->close
)
1659 tty
->ops
->close(tty
, filp
);
1663 * Sanity check: if tty->count is going to zero, there shouldn't be
1664 * any waiters on tty->read_wait or tty->write_wait. We test the
1665 * wait queues and kick everyone out _before_ actually starting to
1666 * close. This ensures that we won't block while releasing the tty
1669 * The test for the o_tty closing is necessary, since the master and
1670 * slave sides may close in any order. If the slave side closes out
1671 * first, its count will be one, since the master side holds an open.
1672 * Thus this test wouldn't be triggered at the time the slave closes,
1675 * Note that it's possible for the tty to be opened again while we're
1676 * flushing out waiters. By recalculating the closing flags before
1677 * each iteration we avoid any problems.
1680 /* Guard against races with tty->count changes elsewhere and
1681 opens on /dev/tty */
1683 mutex_lock(&tty_mutex
);
1684 tty_lock_pair(tty
, o_tty
);
1685 tty_closing
= tty
->count
<= 1;
1686 o_tty_closing
= o_tty
&&
1687 (o_tty
->count
<= (pty_master
? 1 : 0));
1691 if (waitqueue_active(&tty
->read_wait
)) {
1692 wake_up_poll(&tty
->read_wait
, POLLIN
);
1695 if (waitqueue_active(&tty
->write_wait
)) {
1696 wake_up_poll(&tty
->write_wait
, POLLOUT
);
1700 if (o_tty_closing
) {
1701 if (waitqueue_active(&o_tty
->read_wait
)) {
1702 wake_up_poll(&o_tty
->read_wait
, POLLIN
);
1705 if (waitqueue_active(&o_tty
->write_wait
)) {
1706 wake_up_poll(&o_tty
->write_wait
, POLLOUT
);
1713 printk(KERN_WARNING
"%s: %s: read/write wait queue active!\n",
1714 __func__
, tty_name(tty
, buf
));
1715 tty_unlock_pair(tty
, o_tty
);
1716 mutex_unlock(&tty_mutex
);
1721 * The closing flags are now consistent with the open counts on
1722 * both sides, and we've completed the last operation that could
1723 * block, so it's safe to proceed with closing.
1726 if (--o_tty
->count
< 0) {
1727 printk(KERN_WARNING
"%s: bad pty slave count (%d) for %s\n",
1728 __func__
, o_tty
->count
, tty_name(o_tty
, buf
));
1732 if (--tty
->count
< 0) {
1733 printk(KERN_WARNING
"%s: bad tty->count (%d) for %s\n",
1734 __func__
, tty
->count
, tty_name(tty
, buf
));
1739 * We've decremented tty->count, so we need to remove this file
1740 * descriptor off the tty->tty_files list; this serves two
1742 * - check_tty_count sees the correct number of file descriptors
1743 * associated with this tty.
1744 * - do_tty_hangup no longer sees this file descriptor as
1745 * something that needs to be handled for hangups.
1750 * Perform some housekeeping before deciding whether to return.
1752 * Set the TTY_CLOSING flag if this was the last open. In the
1753 * case of a pty we may have to wait around for the other side
1754 * to close, and TTY_CLOSING makes sure we can't be reopened.
1757 set_bit(TTY_CLOSING
, &tty
->flags
);
1759 set_bit(TTY_CLOSING
, &o_tty
->flags
);
1762 * If _either_ side is closing, make sure there aren't any
1763 * processes that still think tty or o_tty is their controlling
1766 if (tty_closing
|| o_tty_closing
) {
1767 read_lock(&tasklist_lock
);
1768 session_clear_tty(tty
->session
);
1770 session_clear_tty(o_tty
->session
);
1771 read_unlock(&tasklist_lock
);
1774 mutex_unlock(&tty_mutex
);
1776 /* check whether both sides are closing ... */
1777 if (!tty_closing
|| (o_tty
&& !o_tty_closing
)) {
1778 tty_unlock_pair(tty
, o_tty
);
1782 #ifdef TTY_DEBUG_HANGUP
1783 printk(KERN_DEBUG
"%s: freeing tty structure...\n", __func__
);
1786 * Ask the line discipline code to release its structures
1788 tty_ldisc_release(tty
, o_tty
);
1790 * The release_tty function takes care of the details of clearing
1791 * the slots and preserving the termios structure. The tty_unlock_pair
1792 * should be safe as we keep a kref while the tty is locked (so the
1793 * unlock never unlocks a freed tty).
1795 release_tty(tty
, idx
);
1796 tty_unlock_pair(tty
, o_tty
);
1798 /* Make this pty number available for reallocation */
1800 devpts_kill_index(inode
, idx
);
1805 * tty_open_current_tty - get tty of current task for open
1806 * @device: device number
1807 * @filp: file pointer to tty
1808 * @return: tty of the current task iff @device is /dev/tty
1810 * We cannot return driver and index like for the other nodes because
1811 * devpts will not work then. It expects inodes to be from devpts FS.
1813 * We need to move to returning a refcounted object from all the lookup
1814 * paths including this one.
1816 static struct tty_struct
*tty_open_current_tty(dev_t device
, struct file
*filp
)
1818 struct tty_struct
*tty
;
1820 if (device
!= MKDEV(TTYAUX_MAJOR
, 0))
1823 tty
= get_current_tty();
1825 return ERR_PTR(-ENXIO
);
1827 filp
->f_flags
|= O_NONBLOCK
; /* Don't let /dev/tty block */
1830 /* FIXME: we put a reference and return a TTY! */
1831 /* This is only safe because the caller holds tty_mutex */
1836 * tty_lookup_driver - lookup a tty driver for a given device file
1837 * @device: device number
1838 * @filp: file pointer to tty
1839 * @noctty: set if the device should not become a controlling tty
1840 * @index: index for the device in the @return driver
1841 * @return: driver for this inode (with increased refcount)
1843 * If @return is not erroneous, the caller is responsible to decrement the
1844 * refcount by tty_driver_kref_put.
1846 * Locking: tty_mutex protects get_tty_driver
1848 static struct tty_driver
*tty_lookup_driver(dev_t device
, struct file
*filp
,
1849 int *noctty
, int *index
)
1851 struct tty_driver
*driver
;
1855 case MKDEV(TTY_MAJOR
, 0): {
1856 extern struct tty_driver
*console_driver
;
1857 driver
= tty_driver_kref_get(console_driver
);
1858 *index
= fg_console
;
1863 case MKDEV(TTYAUX_MAJOR
, 1): {
1864 struct tty_driver
*console_driver
= console_device(index
);
1865 if (console_driver
) {
1866 driver
= tty_driver_kref_get(console_driver
);
1868 /* Don't let /dev/console block */
1869 filp
->f_flags
|= O_NONBLOCK
;
1874 return ERR_PTR(-ENODEV
);
1877 driver
= get_tty_driver(device
, index
);
1879 return ERR_PTR(-ENODEV
);
1886 * tty_open - open a tty device
1887 * @inode: inode of device file
1888 * @filp: file pointer to tty
1890 * tty_open and tty_release keep up the tty count that contains the
1891 * number of opens done on a tty. We cannot use the inode-count, as
1892 * different inodes might point to the same tty.
1894 * Open-counting is needed for pty masters, as well as for keeping
1895 * track of serial lines: DTR is dropped when the last close happens.
1896 * (This is not done solely through tty->count, now. - Ted 1/27/92)
1898 * The termios state of a pty is reset on first open so that
1899 * settings don't persist across reuse.
1901 * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev.
1902 * tty->count should protect the rest.
1903 * ->siglock protects ->signal/->sighand
1905 * Note: the tty_unlock/lock cases without a ref are only safe due to
1909 static int tty_open(struct inode
*inode
, struct file
*filp
)
1911 struct tty_struct
*tty
;
1913 struct tty_driver
*driver
= NULL
;
1915 dev_t device
= inode
->i_rdev
;
1916 unsigned saved_flags
= filp
->f_flags
;
1918 nonseekable_open(inode
, filp
);
1921 retval
= tty_alloc_file(filp
);
1925 noctty
= filp
->f_flags
& O_NOCTTY
;
1929 mutex_lock(&tty_mutex
);
1930 /* This is protected by the tty_mutex */
1931 tty
= tty_open_current_tty(device
, filp
);
1933 retval
= PTR_ERR(tty
);
1936 driver
= tty_lookup_driver(device
, filp
, &noctty
, &index
);
1937 if (IS_ERR(driver
)) {
1938 retval
= PTR_ERR(driver
);
1942 /* check whether we're reopening an existing tty */
1943 tty
= tty_driver_lookup_tty(driver
, inode
, index
);
1945 retval
= PTR_ERR(tty
);
1952 retval
= tty_reopen(tty
);
1955 tty
= ERR_PTR(retval
);
1957 } else /* Returns with the tty_lock held for now */
1958 tty
= tty_init_dev(driver
, index
);
1960 mutex_unlock(&tty_mutex
);
1962 tty_driver_kref_put(driver
);
1964 retval
= PTR_ERR(tty
);
1968 tty_add_file(tty
, filp
);
1970 check_tty_count(tty
, __func__
);
1971 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
1972 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
1974 #ifdef TTY_DEBUG_HANGUP
1975 printk(KERN_DEBUG
"%s: opening %s...\n", __func__
, tty
->name
);
1978 retval
= tty
->ops
->open(tty
, filp
);
1981 filp
->f_flags
= saved_flags
;
1983 if (!retval
&& test_bit(TTY_EXCLUSIVE
, &tty
->flags
) &&
1984 !capable(CAP_SYS_ADMIN
))
1988 #ifdef TTY_DEBUG_HANGUP
1989 printk(KERN_DEBUG
"%s: error %d in opening %s...\n", __func__
,
1992 tty_unlock(tty
); /* need to call tty_release without BTM */
1993 tty_release(inode
, filp
);
1994 if (retval
!= -ERESTARTSYS
)
1997 if (signal_pending(current
))
2002 * Need to reset f_op in case a hangup happened.
2004 if (filp
->f_op
== &hung_up_tty_fops
)
2005 filp
->f_op
= &tty_fops
;
2011 mutex_lock(&tty_mutex
);
2013 spin_lock_irq(¤t
->sighand
->siglock
);
2015 current
->signal
->leader
&&
2016 !current
->signal
->tty
&&
2017 tty
->session
== NULL
)
2018 __proc_set_tty(current
, tty
);
2019 spin_unlock_irq(¤t
->sighand
->siglock
);
2021 mutex_unlock(&tty_mutex
);
2024 mutex_unlock(&tty_mutex
);
2025 /* after locks to avoid deadlock */
2026 if (!IS_ERR_OR_NULL(driver
))
2027 tty_driver_kref_put(driver
);
2029 tty_free_file(filp
);
2036 * tty_poll - check tty status
2037 * @filp: file being polled
2038 * @wait: poll wait structures to update
2040 * Call the line discipline polling method to obtain the poll
2041 * status of the device.
2043 * Locking: locks called line discipline but ldisc poll method
2044 * may be re-entered freely by other callers.
2047 static unsigned int tty_poll(struct file
*filp
, poll_table
*wait
)
2049 struct tty_struct
*tty
= file_tty(filp
);
2050 struct tty_ldisc
*ld
;
2053 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_poll"))
2056 ld
= tty_ldisc_ref_wait(tty
);
2058 ret
= (ld
->ops
->poll
)(tty
, filp
, wait
);
2059 tty_ldisc_deref(ld
);
2063 static int __tty_fasync(int fd
, struct file
*filp
, int on
)
2065 struct tty_struct
*tty
= file_tty(filp
);
2066 unsigned long flags
;
2069 if (tty_paranoia_check(tty
, filp
->f_path
.dentry
->d_inode
, "tty_fasync"))
2072 retval
= fasync_helper(fd
, filp
, on
, &tty
->fasync
);
2079 if (!waitqueue_active(&tty
->read_wait
))
2080 tty
->minimum_to_wake
= 1;
2081 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2084 type
= PIDTYPE_PGID
;
2086 pid
= task_pid(current
);
2090 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2091 retval
= __f_setown(filp
, pid
, type
, 0);
2096 if (!tty
->fasync
&& !waitqueue_active(&tty
->read_wait
))
2097 tty
->minimum_to_wake
= N_TTY_BUF_SIZE
;
2104 static int tty_fasync(int fd
, struct file
*filp
, int on
)
2106 struct tty_struct
*tty
= file_tty(filp
);
2110 retval
= __tty_fasync(fd
, filp
, on
);
2117 * tiocsti - fake input character
2118 * @tty: tty to fake input into
2119 * @p: pointer to character
2121 * Fake input to a tty device. Does the necessary locking and
2124 * FIXME: does not honour flow control ??
2127 * Called functions take tty_ldisc_lock
2128 * current->signal->tty check is safe without locks
2130 * FIXME: may race normal receive processing
2133 static int tiocsti(struct tty_struct
*tty
, char __user
*p
)
2136 struct tty_ldisc
*ld
;
2138 if ((current
->signal
->tty
!= tty
) && !capable(CAP_SYS_ADMIN
))
2140 if (get_user(ch
, p
))
2142 tty_audit_tiocsti(tty
, ch
);
2143 ld
= tty_ldisc_ref_wait(tty
);
2144 ld
->ops
->receive_buf(tty
, &ch
, &mbz
, 1);
2145 tty_ldisc_deref(ld
);
2150 * tiocgwinsz - implement window query ioctl
2152 * @arg: user buffer for result
2154 * Copies the kernel idea of the window size into the user buffer.
2156 * Locking: tty->termios_mutex is taken to ensure the winsize data
2160 static int tiocgwinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2164 mutex_lock(&tty
->termios_mutex
);
2165 err
= copy_to_user(arg
, &tty
->winsize
, sizeof(*arg
));
2166 mutex_unlock(&tty
->termios_mutex
);
2168 return err
? -EFAULT
: 0;
2172 * tty_do_resize - resize event
2173 * @tty: tty being resized
2174 * @rows: rows (character)
2175 * @cols: cols (character)
2177 * Update the termios variables and send the necessary signals to
2178 * peform a terminal resize correctly
2181 int tty_do_resize(struct tty_struct
*tty
, struct winsize
*ws
)
2184 unsigned long flags
;
2187 mutex_lock(&tty
->termios_mutex
);
2188 if (!memcmp(ws
, &tty
->winsize
, sizeof(*ws
)))
2190 /* Get the PID values and reference them so we can
2191 avoid holding the tty ctrl lock while sending signals */
2192 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2193 pgrp
= get_pid(tty
->pgrp
);
2194 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2197 kill_pgrp(pgrp
, SIGWINCH
, 1);
2202 mutex_unlock(&tty
->termios_mutex
);
2207 * tiocswinsz - implement window size set ioctl
2208 * @tty; tty side of tty
2209 * @arg: user buffer for result
2211 * Copies the user idea of the window size to the kernel. Traditionally
2212 * this is just advisory information but for the Linux console it
2213 * actually has driver level meaning and triggers a VC resize.
2216 * Driver dependent. The default do_resize method takes the
2217 * tty termios mutex and ctrl_lock. The console takes its own lock
2218 * then calls into the default method.
2221 static int tiocswinsz(struct tty_struct
*tty
, struct winsize __user
*arg
)
2223 struct winsize tmp_ws
;
2224 if (copy_from_user(&tmp_ws
, arg
, sizeof(*arg
)))
2227 if (tty
->ops
->resize
)
2228 return tty
->ops
->resize(tty
, &tmp_ws
);
2230 return tty_do_resize(tty
, &tmp_ws
);
2234 * tioccons - allow admin to move logical console
2235 * @file: the file to become console
2237 * Allow the administrator to move the redirected console device
2239 * Locking: uses redirect_lock to guard the redirect information
2242 static int tioccons(struct file
*file
)
2244 if (!capable(CAP_SYS_ADMIN
))
2246 if (file
->f_op
->write
== redirected_tty_write
) {
2248 spin_lock(&redirect_lock
);
2251 spin_unlock(&redirect_lock
);
2256 spin_lock(&redirect_lock
);
2258 spin_unlock(&redirect_lock
);
2263 spin_unlock(&redirect_lock
);
2268 * fionbio - non blocking ioctl
2269 * @file: file to set blocking value
2270 * @p: user parameter
2272 * Historical tty interfaces had a blocking control ioctl before
2273 * the generic functionality existed. This piece of history is preserved
2274 * in the expected tty API of posix OS's.
2276 * Locking: none, the open file handle ensures it won't go away.
2279 static int fionbio(struct file
*file
, int __user
*p
)
2283 if (get_user(nonblock
, p
))
2286 spin_lock(&file
->f_lock
);
2288 file
->f_flags
|= O_NONBLOCK
;
2290 file
->f_flags
&= ~O_NONBLOCK
;
2291 spin_unlock(&file
->f_lock
);
2296 * tiocsctty - set controlling tty
2297 * @tty: tty structure
2298 * @arg: user argument
2300 * This ioctl is used to manage job control. It permits a session
2301 * leader to set this tty as the controlling tty for the session.
2304 * Takes tty_mutex() to protect tty instance
2305 * Takes tasklist_lock internally to walk sessions
2306 * Takes ->siglock() when updating signal->tty
2309 static int tiocsctty(struct tty_struct
*tty
, int arg
)
2312 if (current
->signal
->leader
&& (task_session(current
) == tty
->session
))
2315 mutex_lock(&tty_mutex
);
2317 * The process must be a session leader and
2318 * not have a controlling tty already.
2320 if (!current
->signal
->leader
|| current
->signal
->tty
) {
2327 * This tty is already the controlling
2328 * tty for another session group!
2330 if (arg
== 1 && capable(CAP_SYS_ADMIN
)) {
2334 read_lock(&tasklist_lock
);
2335 session_clear_tty(tty
->session
);
2336 read_unlock(&tasklist_lock
);
2342 proc_set_tty(current
, tty
);
2344 mutex_unlock(&tty_mutex
);
2349 * tty_get_pgrp - return a ref counted pgrp pid
2352 * Returns a refcounted instance of the pid struct for the process
2353 * group controlling the tty.
2356 struct pid
*tty_get_pgrp(struct tty_struct
*tty
)
2358 unsigned long flags
;
2361 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2362 pgrp
= get_pid(tty
->pgrp
);
2363 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2367 EXPORT_SYMBOL_GPL(tty_get_pgrp
);
2370 * tiocgpgrp - get process group
2371 * @tty: tty passed by user
2372 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2375 * Obtain the process group of the tty. If there is no process group
2378 * Locking: none. Reference to current->signal->tty is safe.
2381 static int tiocgpgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2386 * (tty == real_tty) is a cheap way of
2387 * testing if the tty is NOT a master pty.
2389 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2391 pid
= tty_get_pgrp(real_tty
);
2392 ret
= put_user(pid_vnr(pid
), p
);
2398 * tiocspgrp - attempt to set process group
2399 * @tty: tty passed by user
2400 * @real_tty: tty side device matching tty passed by user
2403 * Set the process group of the tty to the session passed. Only
2404 * permitted where the tty session is our session.
2406 * Locking: RCU, ctrl lock
2409 static int tiocspgrp(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2413 int retval
= tty_check_change(real_tty
);
2414 unsigned long flags
;
2420 if (!current
->signal
->tty
||
2421 (current
->signal
->tty
!= real_tty
) ||
2422 (real_tty
->session
!= task_session(current
)))
2424 if (get_user(pgrp_nr
, p
))
2429 pgrp
= find_vpid(pgrp_nr
);
2434 if (session_of_pgrp(pgrp
) != task_session(current
))
2437 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
2438 put_pid(real_tty
->pgrp
);
2439 real_tty
->pgrp
= get_pid(pgrp
);
2440 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
2447 * tiocgsid - get session id
2448 * @tty: tty passed by user
2449 * @real_tty: tty side of the tty passed by the user if a pty else the tty
2450 * @p: pointer to returned session id
2452 * Obtain the session id of the tty. If there is no session
2455 * Locking: none. Reference to current->signal->tty is safe.
2458 static int tiocgsid(struct tty_struct
*tty
, struct tty_struct
*real_tty
, pid_t __user
*p
)
2461 * (tty == real_tty) is a cheap way of
2462 * testing if the tty is NOT a master pty.
2464 if (tty
== real_tty
&& current
->signal
->tty
!= real_tty
)
2466 if (!real_tty
->session
)
2468 return put_user(pid_vnr(real_tty
->session
), p
);
2472 * tiocsetd - set line discipline
2474 * @p: pointer to user data
2476 * Set the line discipline according to user request.
2478 * Locking: see tty_set_ldisc, this function is just a helper
2481 static int tiocsetd(struct tty_struct
*tty
, int __user
*p
)
2486 if (get_user(ldisc
, p
))
2489 ret
= tty_set_ldisc(tty
, ldisc
);
2495 * send_break - performed time break
2496 * @tty: device to break on
2497 * @duration: timeout in mS
2499 * Perform a timed break on hardware that lacks its own driver level
2500 * timed break functionality.
2503 * atomic_write_lock serializes
2507 static int send_break(struct tty_struct
*tty
, unsigned int duration
)
2511 if (tty
->ops
->break_ctl
== NULL
)
2514 if (tty
->driver
->flags
& TTY_DRIVER_HARDWARE_BREAK
)
2515 retval
= tty
->ops
->break_ctl(tty
, duration
);
2517 /* Do the work ourselves */
2518 if (tty_write_lock(tty
, 0) < 0)
2520 retval
= tty
->ops
->break_ctl(tty
, -1);
2523 if (!signal_pending(current
))
2524 msleep_interruptible(duration
);
2525 retval
= tty
->ops
->break_ctl(tty
, 0);
2527 tty_write_unlock(tty
);
2528 if (signal_pending(current
))
2535 * tty_tiocmget - get modem status
2537 * @file: user file pointer
2538 * @p: pointer to result
2540 * Obtain the modem status bits from the tty driver if the feature
2541 * is supported. Return -EINVAL if it is not available.
2543 * Locking: none (up to the driver)
2546 static int tty_tiocmget(struct tty_struct
*tty
, int __user
*p
)
2548 int retval
= -EINVAL
;
2550 if (tty
->ops
->tiocmget
) {
2551 retval
= tty
->ops
->tiocmget(tty
);
2554 retval
= put_user(retval
, p
);
2560 * tty_tiocmset - set modem status
2562 * @cmd: command - clear bits, set bits or set all
2563 * @p: pointer to desired bits
2565 * Set the modem status bits from the tty driver if the feature
2566 * is supported. Return -EINVAL if it is not available.
2568 * Locking: none (up to the driver)
2571 static int tty_tiocmset(struct tty_struct
*tty
, unsigned int cmd
,
2575 unsigned int set
, clear
, val
;
2577 if (tty
->ops
->tiocmset
== NULL
)
2580 retval
= get_user(val
, p
);
2596 set
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2597 clear
&= TIOCM_DTR
|TIOCM_RTS
|TIOCM_OUT1
|TIOCM_OUT2
|TIOCM_LOOP
;
2598 return tty
->ops
->tiocmset(tty
, set
, clear
);
2601 static int tty_tiocgicount(struct tty_struct
*tty
, void __user
*arg
)
2603 int retval
= -EINVAL
;
2604 struct serial_icounter_struct icount
;
2605 memset(&icount
, 0, sizeof(icount
));
2606 if (tty
->ops
->get_icount
)
2607 retval
= tty
->ops
->get_icount(tty
, &icount
);
2610 if (copy_to_user(arg
, &icount
, sizeof(icount
)))
2615 struct tty_struct
*tty_pair_get_tty(struct tty_struct
*tty
)
2617 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2618 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2622 EXPORT_SYMBOL(tty_pair_get_tty
);
2624 struct tty_struct
*tty_pair_get_pty(struct tty_struct
*tty
)
2626 if (tty
->driver
->type
== TTY_DRIVER_TYPE_PTY
&&
2627 tty
->driver
->subtype
== PTY_TYPE_MASTER
)
2631 EXPORT_SYMBOL(tty_pair_get_pty
);
2634 * Split this up, as gcc can choke on it otherwise..
2636 long tty_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
2638 struct tty_struct
*tty
= file_tty(file
);
2639 struct tty_struct
*real_tty
;
2640 void __user
*p
= (void __user
*)arg
;
2642 struct tty_ldisc
*ld
;
2643 struct inode
*inode
= file
->f_dentry
->d_inode
;
2645 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
2648 real_tty
= tty_pair_get_tty(tty
);
2651 * Factor out some common prep work
2659 retval
= tty_check_change(tty
);
2662 if (cmd
!= TIOCCBRK
) {
2663 tty_wait_until_sent(tty
, 0);
2664 if (signal_pending(current
))
2675 return tiocsti(tty
, p
);
2677 return tiocgwinsz(real_tty
, p
);
2679 return tiocswinsz(real_tty
, p
);
2681 return real_tty
!= tty
? -EINVAL
: tioccons(file
);
2683 return fionbio(file
, p
);
2685 set_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2688 clear_bit(TTY_EXCLUSIVE
, &tty
->flags
);
2691 if (current
->signal
->tty
!= tty
)
2696 return tiocsctty(tty
, arg
);
2698 return tiocgpgrp(tty
, real_tty
, p
);
2700 return tiocspgrp(tty
, real_tty
, p
);
2702 return tiocgsid(tty
, real_tty
, p
);
2704 return put_user(tty
->ldisc
->ops
->num
, (int __user
*)p
);
2706 return tiocsetd(tty
, p
);
2708 if (!capable(CAP_SYS_ADMIN
))
2714 unsigned int ret
= new_encode_dev(tty_devnum(real_tty
));
2715 return put_user(ret
, (unsigned int __user
*)p
);
2720 case TIOCSBRK
: /* Turn break on, unconditionally */
2721 if (tty
->ops
->break_ctl
)
2722 return tty
->ops
->break_ctl(tty
, -1);
2724 case TIOCCBRK
: /* Turn break off, unconditionally */
2725 if (tty
->ops
->break_ctl
)
2726 return tty
->ops
->break_ctl(tty
, 0);
2728 case TCSBRK
: /* SVID version: non-zero arg --> no break */
2729 /* non-zero arg means wait for all output data
2730 * to be sent (performed above) but don't send break.
2731 * This is used by the tcdrain() termios function.
2734 return send_break(tty
, 250);
2736 case TCSBRKP
: /* support for POSIX tcsendbreak() */
2737 return send_break(tty
, arg
? arg
*100 : 250);
2740 return tty_tiocmget(tty
, p
);
2744 return tty_tiocmset(tty
, cmd
, p
);
2746 retval
= tty_tiocgicount(tty
, p
);
2747 /* For the moment allow fall through to the old method */
2748 if (retval
!= -EINVAL
)
2755 /* flush tty buffer and allow ldisc to process ioctl */
2756 tty_buffer_flush(tty
);
2761 if (tty
->ops
->ioctl
) {
2762 retval
= (tty
->ops
->ioctl
)(tty
, cmd
, arg
);
2763 if (retval
!= -ENOIOCTLCMD
)
2766 ld
= tty_ldisc_ref_wait(tty
);
2768 if (ld
->ops
->ioctl
) {
2769 retval
= ld
->ops
->ioctl(tty
, file
, cmd
, arg
);
2770 if (retval
== -ENOIOCTLCMD
)
2773 tty_ldisc_deref(ld
);
2777 #ifdef CONFIG_COMPAT
2778 static long tty_compat_ioctl(struct file
*file
, unsigned int cmd
,
2781 struct inode
*inode
= file
->f_dentry
->d_inode
;
2782 struct tty_struct
*tty
= file_tty(file
);
2783 struct tty_ldisc
*ld
;
2784 int retval
= -ENOIOCTLCMD
;
2786 if (tty_paranoia_check(tty
, inode
, "tty_ioctl"))
2789 if (tty
->ops
->compat_ioctl
) {
2790 retval
= (tty
->ops
->compat_ioctl
)(tty
, cmd
, arg
);
2791 if (retval
!= -ENOIOCTLCMD
)
2795 ld
= tty_ldisc_ref_wait(tty
);
2796 if (ld
->ops
->compat_ioctl
)
2797 retval
= ld
->ops
->compat_ioctl(tty
, file
, cmd
, arg
);
2799 retval
= n_tty_compat_ioctl_helper(tty
, file
, cmd
, arg
);
2800 tty_ldisc_deref(ld
);
2807 * This implements the "Secure Attention Key" --- the idea is to
2808 * prevent trojan horses by killing all processes associated with this
2809 * tty when the user hits the "Secure Attention Key". Required for
2810 * super-paranoid applications --- see the Orange Book for more details.
2812 * This code could be nicer; ideally it should send a HUP, wait a few
2813 * seconds, then send a INT, and then a KILL signal. But you then
2814 * have to coordinate with the init process, since all processes associated
2815 * with the current tty must be dead before the new getty is allowed
2818 * Now, if it would be correct ;-/ The current code has a nasty hole -
2819 * it doesn't catch files in flight. We may send the descriptor to ourselves
2820 * via AF_UNIX socket, close it and later fetch from socket. FIXME.
2822 * Nasty bug: do_SAK is being called in interrupt context. This can
2823 * deadlock. We punt it up to process context. AKPM - 16Mar2001
2825 void __do_SAK(struct tty_struct
*tty
)
2830 struct task_struct
*g
, *p
;
2831 struct pid
*session
;
2834 struct fdtable
*fdt
;
2838 session
= tty
->session
;
2840 tty_ldisc_flush(tty
);
2842 tty_driver_flush_buffer(tty
);
2844 read_lock(&tasklist_lock
);
2845 /* Kill the entire session */
2846 do_each_pid_task(session
, PIDTYPE_SID
, p
) {
2847 printk(KERN_NOTICE
"SAK: killed process %d"
2848 " (%s): task_session(p)==tty->session\n",
2849 task_pid_nr(p
), p
->comm
);
2850 send_sig(SIGKILL
, p
, 1);
2851 } while_each_pid_task(session
, PIDTYPE_SID
, p
);
2852 /* Now kill any processes that happen to have the
2855 do_each_thread(g
, p
) {
2856 if (p
->signal
->tty
== tty
) {
2857 printk(KERN_NOTICE
"SAK: killed process %d"
2858 " (%s): task_session(p)==tty->session\n",
2859 task_pid_nr(p
), p
->comm
);
2860 send_sig(SIGKILL
, p
, 1);
2866 * We don't take a ref to the file, so we must
2867 * hold ->file_lock instead.
2869 spin_lock(&p
->files
->file_lock
);
2870 fdt
= files_fdtable(p
->files
);
2871 for (i
= 0; i
< fdt
->max_fds
; i
++) {
2872 filp
= fcheck_files(p
->files
, i
);
2875 if (filp
->f_op
->read
== tty_read
&&
2876 file_tty(filp
) == tty
) {
2877 printk(KERN_NOTICE
"SAK: killed process %d"
2878 " (%s): fd#%d opened to the tty\n",
2879 task_pid_nr(p
), p
->comm
, i
);
2880 force_sig(SIGKILL
, p
);
2884 spin_unlock(&p
->files
->file_lock
);
2887 } while_each_thread(g
, p
);
2888 read_unlock(&tasklist_lock
);
2892 static void do_SAK_work(struct work_struct
*work
)
2894 struct tty_struct
*tty
=
2895 container_of(work
, struct tty_struct
, SAK_work
);
2900 * The tq handling here is a little racy - tty->SAK_work may already be queued.
2901 * Fortunately we don't need to worry, because if ->SAK_work is already queued,
2902 * the values which we write to it will be identical to the values which it
2903 * already has. --akpm
2905 void do_SAK(struct tty_struct
*tty
)
2909 schedule_work(&tty
->SAK_work
);
2912 EXPORT_SYMBOL(do_SAK
);
2914 static int dev_match_devt(struct device
*dev
, void *data
)
2917 return dev
->devt
== *devt
;
2920 /* Must put_device() after it's unused! */
2921 static struct device
*tty_get_device(struct tty_struct
*tty
)
2923 dev_t devt
= tty_devnum(tty
);
2924 return class_find_device(tty_class
, NULL
, &devt
, dev_match_devt
);
2929 * initialize_tty_struct
2930 * @tty: tty to initialize
2932 * This subroutine initializes a tty structure that has been newly
2935 * Locking: none - tty in question must not be exposed at this point
2938 void initialize_tty_struct(struct tty_struct
*tty
,
2939 struct tty_driver
*driver
, int idx
)
2941 memset(tty
, 0, sizeof(struct tty_struct
));
2942 kref_init(&tty
->kref
);
2943 tty
->magic
= TTY_MAGIC
;
2944 tty_ldisc_init(tty
);
2945 tty
->session
= NULL
;
2947 tty
->overrun_time
= jiffies
;
2948 tty_buffer_init(tty
);
2949 mutex_init(&tty
->legacy_mutex
);
2950 mutex_init(&tty
->termios_mutex
);
2951 mutex_init(&tty
->ldisc_mutex
);
2952 init_waitqueue_head(&tty
->write_wait
);
2953 init_waitqueue_head(&tty
->read_wait
);
2954 INIT_WORK(&tty
->hangup_work
, do_tty_hangup
);
2955 mutex_init(&tty
->atomic_read_lock
);
2956 mutex_init(&tty
->atomic_write_lock
);
2957 mutex_init(&tty
->output_lock
);
2958 mutex_init(&tty
->echo_lock
);
2959 spin_lock_init(&tty
->read_lock
);
2960 spin_lock_init(&tty
->ctrl_lock
);
2961 INIT_LIST_HEAD(&tty
->tty_files
);
2962 INIT_WORK(&tty
->SAK_work
, do_SAK_work
);
2964 tty
->driver
= driver
;
2965 tty
->ops
= driver
->ops
;
2967 tty_line_name(driver
, idx
, tty
->name
);
2968 tty
->dev
= tty_get_device(tty
);
2972 * deinitialize_tty_struct
2973 * @tty: tty to deinitialize
2975 * This subroutine deinitializes a tty structure that has been newly
2976 * allocated but tty_release cannot be called on that yet.
2978 * Locking: none - tty in question must not be exposed at this point
2980 void deinitialize_tty_struct(struct tty_struct
*tty
)
2982 tty_ldisc_deinit(tty
);
2986 * tty_put_char - write one character to a tty
2990 * Write one byte to the tty using the provided put_char method
2991 * if present. Returns the number of characters successfully output.
2993 * Note: the specific put_char operation in the driver layer may go
2994 * away soon. Don't call it directly, use this method
2997 int tty_put_char(struct tty_struct
*tty
, unsigned char ch
)
2999 if (tty
->ops
->put_char
)
3000 return tty
->ops
->put_char(tty
, ch
);
3001 return tty
->ops
->write(tty
, &ch
, 1);
3003 EXPORT_SYMBOL_GPL(tty_put_char
);
3005 struct class *tty_class
;
3008 * tty_register_device - register a tty device
3009 * @driver: the tty driver that describes the tty device
3010 * @index: the index in the tty driver for this tty device
3011 * @device: a struct device that is associated with this tty device.
3012 * This field is optional, if there is no known struct device
3013 * for this tty device it can be set to NULL safely.
3015 * Returns a pointer to the struct device for this tty device
3016 * (or ERR_PTR(-EFOO) on error).
3018 * This call is required to be made to register an individual tty device
3019 * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If
3020 * that bit is not set, this function should not be called by a tty
3026 struct device
*tty_register_device(struct tty_driver
*driver
, unsigned index
,
3027 struct device
*device
)
3030 dev_t dev
= MKDEV(driver
->major
, driver
->minor_start
) + index
;
3032 if (index
>= driver
->num
) {
3033 printk(KERN_ERR
"Attempt to register invalid tty line number "
3035 return ERR_PTR(-EINVAL
);
3038 if (driver
->type
== TTY_DRIVER_TYPE_PTY
)
3039 pty_line_name(driver
, index
, name
);
3041 tty_line_name(driver
, index
, name
);
3043 return device_create(tty_class
, device
, dev
, NULL
, name
);
3045 EXPORT_SYMBOL(tty_register_device
);
3048 * tty_unregister_device - unregister a tty device
3049 * @driver: the tty driver that describes the tty device
3050 * @index: the index in the tty driver for this tty device
3052 * If a tty device is registered with a call to tty_register_device() then
3053 * this function must be called when the tty device is gone.
3058 void tty_unregister_device(struct tty_driver
*driver
, unsigned index
)
3060 device_destroy(tty_class
,
3061 MKDEV(driver
->major
, driver
->minor_start
) + index
);
3063 EXPORT_SYMBOL(tty_unregister_device
);
3065 struct tty_driver
*__alloc_tty_driver(int lines
, struct module
*owner
)
3067 struct tty_driver
*driver
;
3069 driver
= kzalloc(sizeof(struct tty_driver
), GFP_KERNEL
);
3071 kref_init(&driver
->kref
);
3072 driver
->magic
= TTY_DRIVER_MAGIC
;
3073 driver
->num
= lines
;
3074 driver
->owner
= owner
;
3075 /* later we'll move allocation of tables here */
3079 EXPORT_SYMBOL(__alloc_tty_driver
);
3081 static void destruct_tty_driver(struct kref
*kref
)
3083 struct tty_driver
*driver
= container_of(kref
, struct tty_driver
, kref
);
3085 struct ktermios
*tp
;
3088 if (driver
->flags
& TTY_DRIVER_INSTALLED
) {
3090 * Free the termios and termios_locked structures because
3091 * we don't want to get memory leaks when modular tty
3092 * drivers are removed from the kernel.
3094 for (i
= 0; i
< driver
->num
; i
++) {
3095 tp
= driver
->termios
[i
];
3097 driver
->termios
[i
] = NULL
;
3100 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
))
3101 tty_unregister_device(driver
, i
);
3104 proc_tty_unregister_driver(driver
);
3105 driver
->ttys
= NULL
;
3106 driver
->termios
= NULL
;
3108 cdev_del(&driver
->cdev
);
3113 void tty_driver_kref_put(struct tty_driver
*driver
)
3115 kref_put(&driver
->kref
, destruct_tty_driver
);
3117 EXPORT_SYMBOL(tty_driver_kref_put
);
3119 void tty_set_operations(struct tty_driver
*driver
,
3120 const struct tty_operations
*op
)
3124 EXPORT_SYMBOL(tty_set_operations
);
3126 void put_tty_driver(struct tty_driver
*d
)
3128 tty_driver_kref_put(d
);
3130 EXPORT_SYMBOL(put_tty_driver
);
3133 * Called by a tty driver to register itself.
3135 int tty_register_driver(struct tty_driver
*driver
)
3143 if (!(driver
->flags
& TTY_DRIVER_DEVPTS_MEM
) && driver
->num
) {
3144 p
= kzalloc(driver
->num
* 2 * sizeof(void *), GFP_KERNEL
);
3149 if (!driver
->major
) {
3150 error
= alloc_chrdev_region(&dev
, driver
->minor_start
,
3151 driver
->num
, driver
->name
);
3153 driver
->major
= MAJOR(dev
);
3154 driver
->minor_start
= MINOR(dev
);
3157 dev
= MKDEV(driver
->major
, driver
->minor_start
);
3158 error
= register_chrdev_region(dev
, driver
->num
, driver
->name
);
3166 driver
->ttys
= (struct tty_struct
**)p
;
3167 driver
->termios
= (struct ktermios
**)(p
+ driver
->num
);
3169 driver
->ttys
= NULL
;
3170 driver
->termios
= NULL
;
3173 cdev_init(&driver
->cdev
, &tty_fops
);
3174 driver
->cdev
.owner
= driver
->owner
;
3175 error
= cdev_add(&driver
->cdev
, dev
, driver
->num
);
3177 unregister_chrdev_region(dev
, driver
->num
);
3178 driver
->ttys
= NULL
;
3179 driver
->termios
= NULL
;
3184 mutex_lock(&tty_mutex
);
3185 list_add(&driver
->tty_drivers
, &tty_drivers
);
3186 mutex_unlock(&tty_mutex
);
3188 if (!(driver
->flags
& TTY_DRIVER_DYNAMIC_DEV
)) {
3189 for (i
= 0; i
< driver
->num
; i
++) {
3190 d
= tty_register_device(driver
, i
, NULL
);
3197 proc_tty_register_driver(driver
);
3198 driver
->flags
|= TTY_DRIVER_INSTALLED
;
3202 for (i
--; i
>= 0; i
--)
3203 tty_unregister_device(driver
, i
);
3205 mutex_lock(&tty_mutex
);
3206 list_del(&driver
->tty_drivers
);
3207 mutex_unlock(&tty_mutex
);
3209 unregister_chrdev_region(dev
, driver
->num
);
3210 driver
->ttys
= NULL
;
3211 driver
->termios
= NULL
;
3216 EXPORT_SYMBOL(tty_register_driver
);
3219 * Called by a tty driver to unregister itself.
3221 int tty_unregister_driver(struct tty_driver
*driver
)
3225 if (driver
->refcount
)
3228 unregister_chrdev_region(MKDEV(driver
->major
, driver
->minor_start
),
3230 mutex_lock(&tty_mutex
);
3231 list_del(&driver
->tty_drivers
);
3232 mutex_unlock(&tty_mutex
);
3236 EXPORT_SYMBOL(tty_unregister_driver
);
3238 dev_t
tty_devnum(struct tty_struct
*tty
)
3240 return MKDEV(tty
->driver
->major
, tty
->driver
->minor_start
) + tty
->index
;
3242 EXPORT_SYMBOL(tty_devnum
);
3244 void proc_clear_tty(struct task_struct
*p
)
3246 unsigned long flags
;
3247 struct tty_struct
*tty
;
3248 spin_lock_irqsave(&p
->sighand
->siglock
, flags
);
3249 tty
= p
->signal
->tty
;
3250 p
->signal
->tty
= NULL
;
3251 spin_unlock_irqrestore(&p
->sighand
->siglock
, flags
);
3255 /* Called under the sighand lock */
3257 static void __proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3260 unsigned long flags
;
3261 /* We should not have a session or pgrp to put here but.... */
3262 spin_lock_irqsave(&tty
->ctrl_lock
, flags
);
3263 put_pid(tty
->session
);
3265 tty
->pgrp
= get_pid(task_pgrp(tsk
));
3266 spin_unlock_irqrestore(&tty
->ctrl_lock
, flags
);
3267 tty
->session
= get_pid(task_session(tsk
));
3268 if (tsk
->signal
->tty
) {
3269 printk(KERN_DEBUG
"tty not NULL!!\n");
3270 tty_kref_put(tsk
->signal
->tty
);
3273 put_pid(tsk
->signal
->tty_old_pgrp
);
3274 tsk
->signal
->tty
= tty_kref_get(tty
);
3275 tsk
->signal
->tty_old_pgrp
= NULL
;
3278 static void proc_set_tty(struct task_struct
*tsk
, struct tty_struct
*tty
)
3280 spin_lock_irq(&tsk
->sighand
->siglock
);
3281 __proc_set_tty(tsk
, tty
);
3282 spin_unlock_irq(&tsk
->sighand
->siglock
);
3285 struct tty_struct
*get_current_tty(void)
3287 struct tty_struct
*tty
;
3288 unsigned long flags
;
3290 spin_lock_irqsave(¤t
->sighand
->siglock
, flags
);
3291 tty
= tty_kref_get(current
->signal
->tty
);
3292 spin_unlock_irqrestore(¤t
->sighand
->siglock
, flags
);
3295 EXPORT_SYMBOL_GPL(get_current_tty
);
3297 void tty_default_fops(struct file_operations
*fops
)
3303 * Initialize the console device. This is called *early*, so
3304 * we can't necessarily depend on lots of kernel help here.
3305 * Just do some early initializations, and do the complex setup
3308 void __init
console_init(void)
3312 /* Setup the default TTY line discipline. */
3316 * set up the console device so that later boot sequences can
3317 * inform about problems etc..
3319 call
= __con_initcall_start
;
3320 while (call
< __con_initcall_end
) {
3326 static char *tty_devnode(struct device
*dev
, umode_t
*mode
)
3330 if (dev
->devt
== MKDEV(TTYAUX_MAJOR
, 0) ||
3331 dev
->devt
== MKDEV(TTYAUX_MAJOR
, 2))
3336 static int __init
tty_class_init(void)
3338 tty_class
= class_create(THIS_MODULE
, "tty");
3339 if (IS_ERR(tty_class
))
3340 return PTR_ERR(tty_class
);
3341 tty_class
->devnode
= tty_devnode
;
3345 postcore_initcall(tty_class_init
);
3347 /* 3/2004 jmc: why do these devices exist? */
3348 static struct cdev tty_cdev
, console_cdev
;
3350 static ssize_t
show_cons_active(struct device
*dev
,
3351 struct device_attribute
*attr
, char *buf
)
3353 struct console
*cs
[16];
3359 for_each_console(c
) {
3364 if ((c
->flags
& CON_ENABLED
) == 0)
3367 if (i
>= ARRAY_SIZE(cs
))
3371 count
+= sprintf(buf
+ count
, "%s%d%c",
3372 cs
[i
]->name
, cs
[i
]->index
, i
? ' ':'\n');
3377 static DEVICE_ATTR(active
, S_IRUGO
, show_cons_active
, NULL
);
3379 static struct device
*consdev
;
3381 void console_sysfs_notify(void)
3384 sysfs_notify(&consdev
->kobj
, NULL
, "active");
3388 * Ok, now we can initialize the rest of the tty devices and can count
3389 * on memory allocations, interrupts etc..
3391 int __init
tty_init(void)
3393 cdev_init(&tty_cdev
, &tty_fops
);
3394 if (cdev_add(&tty_cdev
, MKDEV(TTYAUX_MAJOR
, 0), 1) ||
3395 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 0), 1, "/dev/tty") < 0)
3396 panic("Couldn't register /dev/tty driver\n");
3397 device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 0), NULL
, "tty");
3399 cdev_init(&console_cdev
, &console_fops
);
3400 if (cdev_add(&console_cdev
, MKDEV(TTYAUX_MAJOR
, 1), 1) ||
3401 register_chrdev_region(MKDEV(TTYAUX_MAJOR
, 1), 1, "/dev/console") < 0)
3402 panic("Couldn't register /dev/console driver\n");
3403 consdev
= device_create(tty_class
, NULL
, MKDEV(TTYAUX_MAJOR
, 1), NULL
,
3405 if (IS_ERR(consdev
))
3408 WARN_ON(device_create_file(consdev
, &dev_attr_active
) < 0);
3411 vty_init(&console_fops
);